Pituitary oncocytoma presenting as Cushing's disease.

A 19-year-old girl presented with classical features of Cushing's syndrome. Endocrinal evaluation was consistent with pituitary source of ACTH; but imaging showed normal pituitary. Bilateral inferior petrosal sinus sampling confirmed the diagnosis. A successful remission was achieved after adenomectomy by transphenoidal route. Histopathological examination was consistent with pituitary oncocytoma and immunohistochemistry was positive for synaptophysin, chromogranin, neuron specific enolase, S-100, ACTH, prolactin, and GH.

Nelson's syndrome presenting as bilateral oculomotor palsy.

Nelson's syndrome refers to a clinical spectrum arising from progressive enlargement of pituitary adenoma and elevated adrenocorticotrophic hormone after total bilateral adrenalectomy for Cushing's disease comprising of hyperpigmentation, visual field defects which can be life threatening. We report here a 50-year male presenting with rapid onset of Nelson's syndrome with an unusual finding of bilateral oculomotor palsy mistakenly treated as ocular myasthenia.

Combined granulomatous and lymphocytic hypophysitis presenting as pituitary incidentaloma in a middle-aged woman.

We report a case of 41-year-old lady who presented with chronic headache of 6-month duration and a sellar mass with a suprasellar extension on imaging, which was interpreted as pituitary macroadenoma. She had normal pituitary function and visual perimetry. On clinical examination and imaging it was provisionally diagnosed as pituitary incidentaloma due to hypophysitis and she was advised steroid therapy, but underwent transnasal resection of the tumor against suggestion. Histopathological examination revealed combined granulomatous and lymphocytic hypophysitis most likely of autoimmune in origin. Definitive diagnosis of hypophysitis can be made only on histopathological examination. As most cases of autoimmune hypophysitis are surgically treated, patients should be assessed on individual basis for requirement of steroids in postoperative period.

Comparative clinical dosimetry with X-knife and gamma knife.

X-knife and gamma knife techniques are well-established for cranial stereotactic radiosurgery (SRS). Due to differences in their radiation delivery methods, some of the dosimetric parameters of these two techniques differ which may have clinical significance. There are many dosimetric studies comparing linear accelerator based techniques such as X-knife with gamma knife but generally from different institutions. We carried out a retrospective comparative study of the dosimetric parameters of the SRS treatments performed at our centre with X-knife (circular cones) and gamma knife. Our results indicate that the dose conformity and dose fall-off in the vicinity of the target volumes were better for patients treated with gamma knife as compared to X-knife. However, the dose fall-off pattern shows a reversal at a larger distance from the target. It was better for the X-knife as compared to gamma knife in the low dose region.

Primary spinal pleomorphic xanthoastrocytoma.

Pleomorphic xanthochromic astrocytoma primarily of the spinal cord is a rare entity. The case is possibly the fifth such report. Complete surgical excision is the essential requirement for good survival. In the absence of any clearly laid down protocols of adjuvant treatment, anecdotal reports support treatment with chemotherapy alone or both chemotherapy and radiotherapy.

Ethanol biosensors and electrochemical oxidation of NADH.

Comparative studies of the electrochemical oxidation of reduced nicotinamide coenzyme (NADH) at the surfaces of chemically modified graphite paste electrodes (CMEs) are reported. Three different electroactive materials, tetracyanoquinodimethane (TCNQ), tetrathiafulvalene (TTF), and dimethyl ferrocene (dmFc), were used to construct three different chemically modified paste electrodes. The oxidation of NADH was examined on the basis of cyclic voltammetric measurements. The results show that all three mediators (TCNQ, TTF, and dmFc) behave as efficient mediators of the oxidation of NADH. The typical response curves of NADH at the CMEs surfaces are reported. Incorporating alcohol dehydrogenase and electroactive materials (TCNQ, TTF, and dmFc) within the graphite paste electrodes has led to the development of ethanol biosensors. Typical response curves for the ethanol analysis are reported. Comparative studies on the mediated electrochemical responses of the biosensors to ethanol are discussed.